This invention relates to charge pumps and other auxiliary pumps used on hydrostatic transmissions ("HST") for use in light duty applications. Such HSTs can either have their own housing and be attached to an axle driving apparatus, or can be incorporated within a housing that includes the components of the axle driving apparatus. A unit that contains an HST within the housing of an axle driving apparatus is often referred to as a integrated hydrostatic transaxle ("IHT"). The operation of such units are described in U.S. Pat. Nos. 5,201,692 and 5,314,387, the terms of which are incorporated by reference.